Vol 46, No 9 (2019)

The fauna, spatial distribution, and ecological features of oligochaetes and leeches of reservoirs and watercourses of the Ob’ River basin (including Teletskoe Lake and Novosibirsk, Belovskoe, and Gilevskoe reservoirs) have been considered. Published and original data were summarized from 1903 to 2016. Various samplers were used: bottom grabs, scrapers and wash-off from the solid substrates. The assessment of the distribution of oligochaetes in the Ob’ River basin showed that oligochaeto and hirudofauna were formed mainly by eurybiont species, without significant zonal changes. The most common oligochaetes in the Ob’ River basin were Tubifex tubifex (Müller 1774), Limnodrilus hoffmeisteri Claparéde 1862, Spirosperma ferox Eisen 1879, Lumbriculus variegatus (Müller 1773), Stylaria lacustris (Linnaeus 1767), Nais variabilis Piguet. 1906, Chaetogaster diaphanus (Gruithuisen 1828), leeches, Glossiphonia complanata (Linnaeus 1758), Helobdella stagnalis (Linnaeus 1758), and Erpobdella octoculata (Linnaeus 1758). These species were the key components of benthic biocenoses of the water bodies and watercourses of the Ob’–Irtysh interfluve. The species diversity of oligochaetes and leeches in the Ob’ River basin was much less than that in the large basins of Europe (Volga River) and Eastern Siberia (Lake Baikal) and was comparable with the fauna of certain regions of Europe and the Urals. The largest number of species of oligochaetes and leeches was noted in the well-studied basins of the Upper and Middle Ob’ River.

The adaptation of sessile bivalves to the attached mode of life has been studied using three common mytilid species, Mytilus coruscus, Crenomytilus grayanus, and Modiolus modiolus. This study has shown similar features of organization of byssus and some of its structures associated with their functional significance in these bivalves. Myt. coruscus has the shortest and thickest byssal threads with the largest, reinforced attachment disks, which indicates the species’ adaptation to a habitat in the coastal zone with active hydrodynamics. In contrast, the threads of C. grayanus and Mod. modiolus are thinner, longer, and smaller in size, with weakly reinforced attachment disks, which is evidence that these species have adapted to biotopes sheltered from direct wave action.

Information on the distribution and typical biotopes of slugs of the genus Arion in Western Siberia is provided. New localities of A. fasciatus (Nilsson 1823) have been recorded, of which one is a natural biotope located beyond the urban area. The A. subfuscus s. l. complex of cryptic species is represented by only A. fuscus (Müller 1774) individuals of which occur in the subzones of the middle and southern taiga, as well as in aspen/birch forests. A. sibiricus Simroth 1901 is found in the southern taiga subzone.

Temperature and available food are among the key factors affecting fish during their lifetime. The interaction between foraging and thermoregulatory behavioral responses was studied in experimental conditions using 1+ perch individuals. The behavior of fish was examined in a thermally heterogeneous environment with varying levels of food availability: “excessive” (food objects constituted 20% of the overall fish weight in each compartment of the experimental device), “limited” (3%), and “zero” (0%). The values of the final preferred temperatures revealed in these conditions differed significantly: 26, 24, and 22°С, respectively. In the conditions of excessive food, fish locomotor activity was minimal. The food of juvenile fish consumed over 15 minutes was independent of the number of food objects (20 and 3%) in the experimental device, constituting 14.2 and 15.2% of the fish body weight, respectively. However, fish growth was observed only in the first case, probably due to the higher locomotor activity needed to find and obtain food in the environments with fewer food objects. The data presented may be useful for estimating the dominant forms of behavior of juvenile fish both in experimental and field conditions.

From 1985–1998 to 2017, the numbers and structure of the urban population of the goldeneye (Bucephala clangula) were studied in the city of Moscow. Wintering birds and females with ducklings were counted on 150 ponds and 23 creeks of Moscow. Based on the age of ducklings, the date of the onset of egg-laying by females was calculated using the countdown method. The size of the wintering group has grown significantly since 1993 (r_s = 0.92, p < 0.05, n = 25). It reached 2400 birds by 2014. Since 2010, there has been a gradual shift of wintering goldeneyes from outside the city to within its borders. The increase in numbers, like that of the mallard, correlates with local climatic indices: the length of the period of frost (r_s = –0.73, p < 0.05, n = 25) and the mean daily air temperature (r_s = 0.42, p < 0.05, n = 25) do not correlate with the global Index of the North Atlantic Oscillation. The breeding cycles of the goldeneye and mallard are similar in the ordering of the onset of egg-laying in relation to the transition of the average daily air temperature towards over 0°C. The earlier temperatures above freezing are established and the ice melts, the more time the females have to prepare for egg-laying for both goldeneyes (r_s = –0.80, p < 0.05, n = 18) and mallards (r_s = –0.77, p < 0.01, n = 18). In the nesting goldeneye group, in contrast to the mallards, changes were not observed in the timing of reproduction and in the regulation of the negative effects of overstocking, such as an extended egg-laying period and a reduction of brood size in response to increased female numbers. The numbers of nesting goldeneyes grew from 1998 to 2010 up to 57 broods, but in 2017 it dropped to 4. The negative consequences for the local population are primarily associated with winter weather anomalies that lead to the death of trees and their removal by communal services in the habitats of goldeneyes. The goldeneye population sizes in winter and summer vary in the opposite directions, this being caused by multidirectional trends in habitat transformation. The population dynamics of nesting goldeneyes largely depends on the frequency of dangerous meteorological events, while the population dynamics of wintering goldeneyes depends on the regional climate changes.

The first study of a series of papers analyzing the results of a 14-year-long (2004–2017) monitoring of a Slaty-backed Gull population nesting on the roofs in the city of Magadan is presented. Certain peculiarities of the nesting of one of the first urbanized gull populations in northeastern Asia are revealed. As for urban gulls, in contrast to natural nesting, single-pair locations predominate, but the main number of nests is concentrated in several large colonies. When choosing a city as a breeding ground, gulls move increasingly far inland from the sea coast over the years. The location of bird pairs on new sites in the city usually occurs within the sight of the old colony. The growth rate of the colonies averages 13% per year, this being similar to urban gull populations in Europe. The productivity of urban Slaty-backed Gulls nesting on roofs is much higher than in natural colonies. In the urbanized population, there is neither intraspecific predation on eggs nor the death of chicks from neighbor gulls. Most of the nests of urban gulls are built in the same place for many years. The purpose of a construction determines the degree of attendance of its roof by people, this being crucial for the selection of a nesting site by gulls. As a rule, nests are built either around some obstacle on a roof (walls, pipes, superstructures etc.) or in an absolutely open place. The latter strategy is more typical of single pairs. The safety of roofs from predators seems to be the determinative factor that contributes to the urbanization of gulls.

To test the hypothesis that birds shift song parameters to higher frequencies in response to continuous low-frequency noise, we received records of vocalizations from 78 male chaffinchs in Moscow city parks. The levels of noise were recorded for each recording point. Based on phonograms, we measured the minimum frequency of four phrases in three common songs types in Moscow. Measurements of each phrase were made in 18–21 males with measurement of four songs of a given type in each male, which were randomly selected from a phonogram. The minimum frequency in the vocalizations of various males varied from 4.94 to 5.22 kHz for phrase 1, from 2.23 to 2.6 kHz for phrase 2, from 1.77 to 2.64 kHz for phrase 3, and from 2.08 to 2.42 kHz for phrase 4. A significant positive correlation (the Pearson correlation coefficient, 0.67 < r < 0.79) of the minimum frequency with the noise level was revealed for three out of the four phrases studied. A sharp increase in the minimum frequency of singing with increased noise was revealed at a noise level of 55 dB and above.

The Far Eastern leopard, Panthera pardus orientalis, is one of the rarest subspecies of large cats in the world. Its numbers used to be estimated at 25–50 individuals. New methods of research using automatic cameras and molecular-genetic diagnostics have failed to provide exhaustive information as well. Our work was carried out in 2011–2013 in the southwestern part of Primorskii krai: from the Razdolnaya River in the northeast to the border with North Korea in the south and China in the southwest. We chose a model area of ​​503 km², where we installed a network of 41 pairs of Reconyx Rapidfire RC60, HC500, HC600 photo traps, high-speed automatic digital cameras with infrared motion sensors and infrared illumination, allowing us to obtain one frame per second. Information was removed from the photo traps once every four months. Two methods were used to survey the leopard population: direct extrapolation of the number of registered leopards during the year over the model area across the subspecies’ entire distribution area; and a modified method of the Capture program utilized to determine the population density, which is also based on the principle of recatching, taking into account the spatial relationships between animal registrations (Space Capture-Recapture, SECR) when using the SPACECAP program. The “effective trapping area” was determined for correct extrapolations, one designed as a variant of half the average distance between two recaptures (1/2MMDM). This allowed us to obtain a buffer zone with a width of 5.66 km. The “effective trapping area” amounted to 1023 km². Apparently unsuitable habitats were excluded from this area. In 377 pictures obtained with photo traps, we identified 27 leopards. Ten of them were males, ten, females, and seven individuals remained unsexed, while ten individuals were unidentified. Extrapolating these data to the entire territory taken up by potential leopard habitats in the Russian Far East, i.e., over an area of 3502 km², allows us to conclude that the numbers of leopards total about 96–100 individuals, of which about 60 animals are resident and 35–40 are young, nomadic individuals. However, given the previous counts of leopard numbers, traces of which were found in an area of 2233 km², the overall estimate of the population is likely to be lower and will be about 60–65 leopards.

For the first time, satellite telemetry has been used to study migrations of a mature male of the Ladoga seal (Pusa hispida ladogensis). During the entire period of tracking (from November 2017 to February 2018), the seal moved only in the southeastern part of Lake Ladoga, occasionally entering the estuaries of larger rivers. These areas are highly bioproductive and have high food concentrations. Before ice formation, the seal preferred shallow coastal areas with a high anthropogenic pressure. After ice formation, the seal moved to deeper ice-free areas of the lake.

In laboratory experiments we investigate hunting behavior towards insects in Phodopus sungorus (Pallas 1773), P. сampbelli (Thomas 1905), Allocricetulus eversmanni (Brandt 1859), and A. curtatus (Allen 1925). In these species purposeful inter-relations with insects in the predator–prey manner have been revealed and described in details. In all species investigated, the patterns of hunting behavior are comparable with those of specialized predator hamsters. In a quarter of all cases, hamsters start attacks by seizing the prey with their paws, which is considering more evolutionary progressive than capturing with their teeth. The Djungarian hamster P. sungorus demonstrates the simplest pattern of hunting, whereas in other species some features of specialization have been revealed, such as different forms of manipulation activity. A. curtatus displays the swiftest and most effective attacks towards prey. We speculate that the obligatory innate patterns of hunting in both Allocricetulus species are connected with more specialized predatory behavior of members of this more evolutionary young group as compared to members of the genus Phodopus, with their optional hunting patterns which need experience to be completed.